2020-06-16 01:37:57

by Yang Shi

[permalink] [raw]
Subject: [PATCH] mm: thp: remove debug_cow switch

Since commit 3917c80280c93a7123f1a3a6dcdb10a3ea19737d ("thp: change CoW
semantics for anon-THP"), the CoW page fault of THP has been rewritten,
debug_cow is not used anymore. So, just remove it.

Cc: Kirill A. Shutemov <[email protected]>
Signed-off-by: Yang Shi <[email protected]>
---
include/linux/huge_mm.h | 7 -------
mm/huge_memory.c | 21 ---------------------
2 files changed, 28 deletions(-)

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 71f2077..b8d7c36 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -181,13 +181,6 @@ static inline bool transhuge_vma_suitable(struct vm_area_struct *vma,
#define transparent_hugepage_use_zero_page() \
(transparent_hugepage_flags & \
(1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG))
-#ifdef CONFIG_DEBUG_VM
-#define transparent_hugepage_debug_cow() \
- (transparent_hugepage_flags & \
- (1<<TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG))
-#else /* CONFIG_DEBUG_VM */
-#define transparent_hugepage_debug_cow() 0
-#endif /* CONFIG_DEBUG_VM */

extern unsigned long thp_get_unmapped_area(struct file *filp,
unsigned long addr, unsigned long len, unsigned long pgoff,
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 78c84be..2f585d2 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -303,24 +303,6 @@ static ssize_t hpage_pmd_size_show(struct kobject *kobj,
static struct kobj_attribute hpage_pmd_size_attr =
__ATTR_RO(hpage_pmd_size);

-#ifdef CONFIG_DEBUG_VM
-static ssize_t debug_cow_show(struct kobject *kobj,
- struct kobj_attribute *attr, char *buf)
-{
- return single_hugepage_flag_show(kobj, attr, buf,
- TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG);
-}
-static ssize_t debug_cow_store(struct kobject *kobj,
- struct kobj_attribute *attr,
- const char *buf, size_t count)
-{
- return single_hugepage_flag_store(kobj, attr, buf, count,
- TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG);
-}
-static struct kobj_attribute debug_cow_attr =
- __ATTR(debug_cow, 0644, debug_cow_show, debug_cow_store);
-#endif /* CONFIG_DEBUG_VM */
-
static struct attribute *hugepage_attr[] = {
&enabled_attr.attr,
&defrag_attr.attr,
@@ -329,9 +311,6 @@ static ssize_t debug_cow_store(struct kobject *kobj,
#ifdef CONFIG_SHMEM
&shmem_enabled_attr.attr,
#endif
-#ifdef CONFIG_DEBUG_VM
- &debug_cow_attr.attr,
-#endif
NULL,
};

--
1.8.3.1


2020-06-16 17:38:15

by Zi Yan

[permalink] [raw]
Subject: Re: [PATCH] mm: thp: remove debug_cow switch

On 15 Jun 2020, at 21:29, Yang Shi wrote:

> Since commit 3917c80280c93a7123f1a3a6dcdb10a3ea19737d ("thp: change CoW
> semantics for anon-THP"), the CoW page fault of THP has been rewritten,
> debug_cow is not used anymore. So, just remove it.
>
> Cc: Kirill A. Shutemov <[email protected]>
> Signed-off-by: Yang Shi <[email protected]>
> ---

Makes sense to me.

Reviewed-by: Zi Yan <[email protected]>


Best Regards,
Yan Zi


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